4. Jamaal Charles, Kansas City Chiefs

Twice now, Charles’s career has been derailed by an ACL injury. The latest setback came five games into a promising start to 2015—a vintage Charles performance in which he was dangerous both as a runner (5.1 yards per attempt) and a receiver (on pace for 67 receptions when he got hurt). At 100% he is an ideal back for the modern game, a three-down playmaker with more than enough evasiveness and speed to be deadly in the open field. On that note, it’s easy to forget that Charles also was a dangerous return man early in his career. He nearly hit 1,000 kick-return yards in 2009, paced by a 97-yard TD vs. Pittsburgh. The Chiefs long ago took him out of that role because he was too valuable to their offense, but the skill set that worked on special teams still gets the job done. Now, if he could just stay healthy.